Zigzag actuating mechanism for sewing machines



Oct. 1, 1963 .1. szosTAK ETAL 3,105,449

ZIGZAG ACTUATING MECHANISM FOR SEWING MACHINES Filed March 16, 1961 INVENTORS. JAN .Szosmk and Louis R. BROFSKY BY.

WITNESS.

m z a o United States Patent 3,105,449 ZIGZAG ACTUATING MECHM FOR SEWING MACHENES Han Szostak, Linden, and Louis R. rotsky, Elizabeth,

Ni, assignors to The Singer Company, a corporation of New Jersey Filed Mar. 16, 1961, Ser. No. 96,235 2 Claims. ((11. 112-158) The present invention relates to a zigzag actuating mechanism for the needle bar of a sewing machine and has for an object to provide such a mechanism that is simple and economical, dependable and efiicient.

In accordance with this invention, there has been provided means for imparting lateral vibrations to the needle bar of the sewing machine, which means includes a pitman connected at one end to the needle bar mechanism and, at the other end, is connected to a pivotally mounted oscillating block for adjustment radially relatively to the pivotal axis of the block. In particular, the present invention relates to mechanism for imparting oscillation to the block, and includes a follower pivotally connected to the block at a point spaced from the pivot axis thereof and having opposed faces embracing a cam rotatably mounted in the machine and means for confining the follower against lateral movement relatively to the cam. Further features of the invention are the formation of the confining means as a fork secured to the follower, the formation of the cam on a sleeve on which is also formed a gear by means of which the cam is rotated, the use of a pivot screw for rotatably mounting the sleeve, the provision of a flange on the cam that is embraced on its opposite faces by the follower and the fork to hold the follower in operative relation, and arranging the various elements so that the fork cooperates with the head of the stud on which the sleeve is journaled.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and ar rangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detfi as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

FIG. 1 is a horizontal sectional view through the upper portion of a sewing machine embodying the present in: vention.

FIG. 2 is a fragmentary sectional view, taken substantimly on the line 2-2 of FIG. 1.

FIG. 3 is a fragmentary sectional view taken substantially on the line 3-3 of FIG. 1.

With reference to the drawings, there is illustrated a bracket arm 1 of the frame of a sewing machine, which bracket arm terminates in a head 2. Journaled longitudinally of the bracket arm 1 is a main shaft 3. Power is delivered to the main shaft 3 by means of a worm wheel 4 meshing with a worm 5 on a driven shaft 6.

A needle bar 7 is mounted in the head 2 for endwise reciprocation and is adapted to be vibrated laterally of the line of seam formation by means of a crank 8 pivotally mounted intermediate its end on the presser bar bushing 9 and connected at its forward end to the upper portion of the needle bar and pivotally connected at its rearward ice end to one end of a link 10. At its opposite end, the link 1% is pivotally connected to a slide 11 mounted in an arcuate slideway 12 in a block 13 that is pivotally mounted at its forward end by a pivot screw 14 on :1 plate 15. The plate 15 is in turn pivotally mounted at its rearward end in the bracket arm 1 by a pivot screw 16. An arm 17 of a follower 13 extends between the plate 15 and block 13 and is pivotally connected to the free end of the block 13 by a pin 19.

The follower 18 is formed with opposed planar faces 20 embracing the opposite faces of a cam 21 formed on a sleeve 22. that is journaled on a vertical axis stud 23 in the form of a pivot screw mounted in the bracket arm. Rotation is imparted to the sleeve 22 from the main shaft 3 by gear 24 and worm 25. To hold the faces 20 in engagement with the cam 21, the follower 18 is guided or confined for movement substantially along a line defined by the axes of the pin 19 and the stud 23 by a fork 26 secured by screws 27 to the top surface of the follower 18 and having opposed faces embracing the head 28 of the stud 23, which head also holds the sleeve on the stud 23. The top of the sleeve 22 is formed with a flange 29 embraced by the follower 18 and the fork 26 to support the follower axially of the stud 23. The cam 21 is of the conventional three-corner type which provides a dwell in the actuation imparted to the follower 18. In this manner, the needle bar 7 is not moved laterally while in the down position, which is when the needle is in the work.

Upon rotation of the main shaft 3, rotation is imparted to the sleeve 22, which, through the cam 21, imparts actuation to the follower 18 and which in turn oscillates the block 13 and thus the slide 11 about the axis of the screw 14. Through the link 10, oscillation of the block 13 and slide 11 effects lateral vibration of the needle bar. The amplitude of the lateral vibration is determined by the setting of the slide 11 radially of the pivot axis of block 13, which is the screw 14. Adjustment of the slide 11 along the slideway 12 to vary the amplitude of oscillation of the slide 11 is effected by an operator adjusted bell crank lever 30 pivotally mounted in the bracket arm 11 by a pivot screw 31 and having a pin 32 projecting upwardly into a slot 33 in the link 19 intermediate the ends thereof. Adjustment of the field or center of the zigzag pattern is effected by an operator adjusted lever 34 secured to the plate 15 and adapted to shift the plate 15 about the pivot axis defined by the screw 16 and thus shift the pivot axis of the block 13 defined by the pivot screw 14.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be const'ued as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

'Having thus set forth the nature of the invention, what we claim herein is:

-1. Zigzag mechanism for a sewing machine having an endwise reciprocatory and laterally vibratory needle bar, comprising a block having a slideway, means for pivotaliy mounting said block to define a pivot axis and providing for shifting the pivot axis thereof to effect center adjustment of the zigzag pattern, a slide mounted in said slideway, a needle bar driving link connected at one end to said slide and at the other end to said needle bar, and means for imparting oscillation to said block comprising a stud, a sleeve journaled on said stud, means for imparting rotation to said sleeve, a cam on said sleeve, a follower having opposed faces operatively engaging said cam,

means for pivotally connecting said follower to said block at a point spaced from the pivot axis of said block, means for confining said follower to motion substantially along a line defined by the axes of said stud and of the pivotal connection between said follower and said block comprising a fork secured to said follower and having opposed faces operatively engaging said stud, and means for supporting said follower axially on said sleeve comprising a flange extending laterally from said sleeve and embraced on the opposite sides thereof by said follower and said fork.

References Cited in the file of this patent UNITED STATES PATENTS 1,434,398 Moulton Nov. 7, 1922 1,997,411 Eames Apr. 9, 1935 2,755,754 Urscheler July 24, 1956 2,887,967 Kasper et al May 26, 1959 2,900,937 Gegauf s Aug. 25, 1959 FOREIGN PATENTS 164,513 Switzerland Dec. 16, 1933 

1. ZIGZAG MECHANISM FOR A SEWING MACHINE HAVING AN ENDWISE RECIPROCATORY AND LATERALLY VIBRATORY NEEDLE BAR, COMPRISING A BLOCK HAVING A SLIDEWAY, MEANS FOR PIVOTALLY MOUNTING SAID BLOCK TO DEFINE A PIVOT AXIS AND PROVIDING FOR SHIFTING THE PIVOT AXIS THEREOF TO EFFECT CENTER ADJUSTMENT OF THE ZIGZAG PATTERN, A SLIDE MOUNTED IN SAID SLIDEWAY, A NEEDLE BAR DRIVING LINK CONNECTED AT ONE END TO SAID SLIDE AND AT THE OTHER END TO SAID NEEDLE BAR, AND MEANS FOR IMPARTING OSCILLATION TO SAID BLOCK COMPRISING A STUD, A SLEEVE JOURNALED ON SAID STUD, MEANS FOR IMPARTING ROTATION TO SAID SLEEVE, A CAM ON SAID SLEEVE, A FOLLOWER HAVING OPPOSED FACES OPERATIVELY ENGAGING SAID CAM, MEANS FOR PIVOTALLY CONNECTING SAID FOLLOWER TO SAID BLOCK AT A POINT SPACED FROM THE PIVOT AXIS OF SAID BLOCK, MEANS FOR CONFINING SAID FOLLOWER TO MOTION SUBSTANTIALLY ALONG A LINE DEFINED BY THE AXES OF SAID STUD AND OF THE PIVOTAL CONNECTION BETWEEN SAID FOLLOWER AND SAID BLOCK COMPRISING A FORK SECURED TO SAID FOLLOWER AND HAVING OPPOSED FACES OPERATIVELY ENGAGING SAID STUD, AND MEANS FOR SUPPORTING SAID FOLLOWER AXIALLY ON SAID SLEEVE COMPRISING A FLANGE EXTENDING LATERALLY FROM SAID SLEEVE AND EMBRACED ON THE OPPOSITE SIDES THEREOF BY SAID FOLLOWER AND SAID FORK. 